Dual regulation of NR2B and NR2C expression by NMDA receptor activation in mouse cerebellar granule cell cultures
Dual regulation of NR2B and NR2C expression by NMDA receptor activation in mouse cerebellar granule cell cultures
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DOI：
10.1073/pnas.0805574105
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发表时间：
2008-08-19
影响因子：
11.1
通讯作者：
Nakanishi, Shigetada
中科院分区：
文献类型：
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作者：
Iijima, Kouichirou;Abe, Haruka;Nakanishi, Shigetada
在发育中的小脑中，NMDA受体的亚基组成的转换发生在颗粒细胞中，从含NR 2B的受体到含NR 2C的受体。我们研究了生理KCl浓度（5 mM）下小鼠颗粒细胞原代培养物中NR 2B和NR 2C亚基组成的转换机制。颗粒细胞广泛延长其神经突48小时后，已培养在无血清培养基中含有5 mM KCl。与这种形态学变化相一致，NR 2B mRNA和NR 2C mRNA分别在颗粒细胞中下调和上调。通过用TTX阻断颗粒细胞的兴奋，这两种mRNA的双重调节被废除。这种NR 2B和NR 2C mRNA的神经元活性依赖性调节通过添加AMPA受体和NMDA受体的选择性拮抗剂而被废除。此外，在TTX处理的细胞中，NR 2B和NR 2C mRNA的双重调节通过在AMPA受体拮抗剂的存在下加入NMDA而恢复，但在NMDA受体拮抗剂的存在下不通过AMPA而恢复。重要的是，NMDA受体激活驱动颗粒细胞表面膜上NMDA受体的NR 2B/NR 2C转换。这项调查表明，NMDA受体的刺激与AMPA受体介导的颗粒细胞的兴奋起着关键作用，在生理KCl浓度的成熟颗粒细胞中的NMDA受体的功能亚基开关。
In the developing cerebellum, switching of the subunit composition of NMDA receptors occurs in granule cells from NR2B-containing receptors to NR2C-containing ones. We investigated the mechanisms underlying switching of NR2B and NR2C subunit composition in primary cultures of mouse granule cells at the physiological KCl concentration (5 mM). Granule cells extensively extended their neuritic processes 48 h after having been cultured in serum-free medium containing 5 mM KCl. Consistent with this morphological change, NR2B mRNA and NR2C mRNA were down-and up-regulated, respectively, in the granule cells. This dual regulation of the two mRNAs was abrogated by blocking excitation of granule cells with TTX. This neuronal activity-dependent regulation of NR2B and NR2C mRNAs was abolished by the addition of selective antagonists of AMPA receptors and NMDA receptors. Furthermore, the dual regulation of NR2B and NR2C mRNAs in TTX-treated cells was restored by the addition of NMDA in the presence of the AMPA receptor antagonist, but not by that of AMPA in the presence of the NMDA receptor antagonist. Importantly, the NMDA receptor activation drove the NR2B/NR2C switching of NMDA receptors in the cell-surface membrane of granule cells. This investigation demonstrates that stimulation of NMDA receptors in conjunction with the AMPA receptor-mediated excitation of granule cells plays a key role in functional subunit switching of NMDA receptors in maturing granule cells at the physiological KCl concentration.